Mirtazapine
Mirtazapine is an antidepressant (a noradrenergic and specific serotonergic antidepressant, NaSSA). In the UK it is commonly prescribed for major depression, especially when poor sleep or appetite is a problem, when your prescriber thinks it is appropriate.
This medicine is part of the Mental health medicines category.
Generic name: mirtazapine
Quick answers
Short replies to searches people often run before speaking to a clinician. For the overview of what the medicine is used for, see the short summary under the page title above.
What is it for?
Mirtazapine is an antidepressant (a noradrenergic and specific serotonergic antidepressant, NaSSA).
How long does it take to work?
Many antidepressants need several weeks on a steady dose before full benefit; your GP usually reviews you in that window.
What are common side effects?
Common effects include drowsiness, increased appetite, weight gain, dry mouth, constipation, and feeling sluggish the next day if the dose is high for you.
Can you take paracetamol or ibuprofen with it?
Ask your GP or pharmacist before taking Mirtazapine with paracetamol or ibuprofen. Many adults use paracetamol for short periods when appropriate; NSAIDs such as ibuprofen need extra checks with your other medicines and health conditions.
More about what Mirtazapine is used for
Mirtazapine is an antidepressant (a noradrenergic and specific serotonergic antidepressant, NaSSA). In the UK it is commonly prescribed for major depression, especially when poor sleep or appetite is a problem, when your prescriber thinks it is appropriate.
It may occasionally be used for other conditions under specialist guidance. Treatment usually includes follow-up and may combine with talking therapies.
How does Mirtazapine work, and how long does it take to work?
It affects several chemical messengers in the brain, including serotonin and noradrenaline, which is thought to improve mood and sleep pattern in some people.
Unlike some antidepressants, it often causes drowsiness at lower doses, which is why it is frequently taken at night.
How and when should you take Mirtazapine?
Mirtazapine is usually taken once daily at bedtime. Swallow tablets with water, with or without food — follow your prescription and leaflet.
Do not stop suddenly without medical advice; your GP may recommend a gradual dose reduction.
What are the common side effects of Mirtazapine?
Common effects include drowsiness, increased appetite, weight gain, dry mouth, constipation, and feeling sluggish the next day if the dose is high for you.
Many side effects are worst in the first weeks. Speak to your GP if weight gain or sedation is a concern.
Serious side effects of Mirtazapine — when to get urgent help
Seek urgent help for thoughts of self-harm, severe agitation, fever with sore throat or mouth ulcers (blood disorder warning in leaflet), yellowing of skin or eyes, or severe allergic reaction.
A rare reaction is serotonin syndrome if combined wrongly with other serotonergic drugs — seek urgent help for confusion, high fever, muscle stiffness, or shivering.
What if you miss a dose of Mirtazapine?
If you miss a dose, skip it and take your next dose at the usual time the following night unless your prescriber advises otherwise. Do not double up.
If you miss several doses, contact your GP for advice on restarting.
Who should not take Mirtazapine?
Mirtazapine is not used with MAOIs or within the unsafe interval after stopping an MAOI. Caution in epilepsy, liver disease, bipolar disorder, diabetes, and angle-closure glaucoma risk.
St John’s wort must not be combined with mirtazapine. Always list all medicines.
Can you take paracetamol or ibuprofen with Mirtazapine? — other interactions
Sedative medicines, alcohol, Tramadol, and other antidepressants can increase drowsiness or serotonin risk. Always check with a pharmacist before new tablets.
Mirtazapine in pregnancy and breastfeeding
Discuss with your GP or psychiatrist before changing mirtazapine in pregnancy or breastfeeding — decisions balance risks of untreated depression with medicine safety.
Blood tests and monitoring on Mirtazapine
Your prescriber may review mood, weight, blood glucose if you have diabetes, and cholesterol after starting or changing dose.
What might your GP prescribe instead of Mirtazapine?
Your GP may consider SSRIs, SNRIs, or other approaches depending on symptoms, past response, and side effects.
Reviewed by UK registered pharmacists
Reviewed by UK registered pharmacists for accuracy and clarity. Content is informational only.
- Professional registration
- GPhC registration number: [placeholder — to be added when verified]
- Last reviewed
Frequently asked questions about Mirtazapine
People also ask — common Google searches
- What is Mirtazapine used for?
- Mirtazapine is an antidepressant (a noradrenergic and specific serotonergic antidepressant, NaSSA). In the UK it is commonly prescribed for major depression, especially when poor sleep or appetite is a problem, when your prescriber thinks it is appropriate.
- How long does Mirtazapine take to work?
- Many antidepressants need several weeks on a steady dose before full benefit; your GP usually reviews you in that window. Always follow your prescriber’s follow-up plan.
- Can you take Mirtazapine with paracetamol or ibuprofen?
- Ask your GP or pharmacist before taking Mirtazapine with Paracetamol or Ibuprofen. Many adults use paracetamol for short periods when appropriate; NSAIDs such as ibuprofen need extra checks with your other medicines and health conditions.
- What are the side effects of Mirtazapine?
- Common effects include drowsiness, increased appetite, weight gain, dry mouth, constipation, and feeling sluggish the next day if the dose is high for you. Many side effects are worst in the first weeks. See the sections below for more detail, including serious side effects and when to seek urgent help.
- Why does mirtazapine make me sleepy?
- It has strong antihistamine-like effects at lower doses, which often helps insomnia linked to depression. That is why it is usually taken at night.
- Will mirtazapine make me gain weight?
- Increased appetite and weight gain are common. If this worries you, speak to your GP — they may review diet support or consider alternatives.
Need personalised advice?
Your local pharmacist or GP surgery can help with questions about your medicines, side effects, and alternatives that may be suitable for you.
Links open the NHS website for finding services. DrugABC does not sell prescription-only medicines or replace clinical care.
Often used with
People searching for Mirtazapine often read about these medicines too — for example when treatments are combined under GP or specialist care. This is not a prescribing suggestion.
Related medicines
You may also find these informational pages helpful. Each link opens a full guide on DrugABC. Your prescriber decides what is appropriate for you.